The monkey's striate cortex is divided into at least two independent and overlapping systems of vertical columns of cells. In one type cells with the same axis orientation are grouped together; in the second set cells are grouped according to eye preference. I have preliminary evidence that color-sensitive cells are also arranged in columns. I shall attempt to determine the detailed organization of these columns of color-sensitive cells and examine the relationship of them to the first two types. I shall endeavor to learn whether color columns are defined in terms of general color responses or whether the cells in a column are even more specific in their responses to different wavelengths. I will also investigate the distribution of the color cells in the different layers of the monkey's striate cortex and try to deduce from this information how the color-sensitive neutrons are synaptically connected. I have preliminary evidence that the concentric and simple color cells are confined to layer IV while the complex and hypercomplex color cells are found above and below this level. Finally, since the four dorsal layers of the lateral geniculate nucleus project to cortical layers IVC and IVA while the two ventral magnocellular layers send axons to IVB, it would be interesting to carefully examine the properties of cells in these three subdivisions of layer IV.